Employees of CAE-Link Tactical Simulation Systems, a maker of anti-submarine warfare simulators for the Navy, said yesterday they fear the firm is about to close its Silver Spring plant and lay off 600 employees.

But officials at CAE-Link's parent company in Canada are staying mum about their plans, except to confirm that they are reviewing the plant's future.

The employees said the shift of some business to another plant in Upstate New York, and recent company statements about the need for consolidation, have them worried about their jobs at CAE-Link, which has been caught in a maelstrom of corporate takeover activity in recent years.

"The prospects for ... this plant even staying open are severely reduced," said Michael Meiselman, president of Local 1140 of the International Association of Machinists and Aerospace Workers, which represents 80 workers at the plant. The union yesterday organized a demonstration by union and salaried workers outside the plant, on Tech Road in Silver Spring, to call attention to what they believe is the impending closing.

A spokesman for CAE Industries, a Toronto-based electronics company that purchased the Link operation two years ago, said yesterday the firm is reviewing the future of the Silver Spring plant but had not yet made a decision.

"Like all the companies in the U.S. defense business, we're restructuring ourselves to ensure our viability in a rapidly changing market," said the spokesman, Fred Fraser. "We intend to remain a strong and intensely competitive player in the niches that we now occupy."

Although Meiselman said the company has told employees a decision will be made in two or three weeks, Fraser declined to comment on timing. "A decision that affects the employees will be communicated at the appropriate time," Fraser said.

CAE bought the Silver Spring plant as part of a package of operations it purchased in July 1988 from Singer Co., which itself had been taken over a few months earlier by investor Paul A. Bilzerian, who was fined and sentenced to prison in 1989 for securities and tax fraud related to the Singer takeover.

The operations purchased by CAE from Singer included a small Alexandria defense contractor, Allen Corp. of America, which CAE earlier this year merged into another operation, resulting in a number of layoffs. Fraser declined to say how many workers were laid off at the Alexandria facility.

Link is a leading name in simulators used to train aircraft and helicopter pilots and other specialized personnel. The Silver Spring plant -- once used to make aircraft simulators -- now manufactures devices used to train sailors to operate sophisticated ground- and ship-based anti-submarine warfare equipment.

Meiselman, who said employment at the Silver Spring facility has fallen from a peak of 2,000 a few years ago as a result of the Bilzerian takeover and other corporate machinations, said CAE seems to be transferring work from the plant to another, much larger facility in Binghamton, N.Y., where CAE-Link is based.

Should the plant be closed, Meiselman said, it likely would be difficult for many of its workers to find jobs. Although some employees with simulator-specific skills might find jobs in the Washington area, which has a large number of simulator manufacturers, he said, "as far as the rest of us goes, the job market is pretty tight."